Industrial control systems or controllers are employed for controlling operation of a wide variety of systems, including processes, machines, etc., and are typically adaptable to different control applications through configuration and interconnection of multiple control system components or devices, such as control modules, I/O modules, I/O devices, etc. Modern industrial control systems typically include a processor running or executing a control program to interact with an I/O system (e.g., typically one or more I/O modules or devices) to receive system information in the form of analog and/or digital inputs from field sensors and to provide outputs (analog and/or digital) to one or more actuators. Industrial control systems are more and more being interconnected with management information and other systems in a manufacturing facility and may be operatively connected to any number of communications networks to facilitate various business management functions such as inventory control, accounting, manufacturing control, etc., in addition to the process/machine control functionality. A continuing goal is thus to allow users throughout a given enterprise to access manufacturing data from any location, at any time, and to integrate this data seamlessly with business information systems. In the past, however, this integration of business and control systems has required extensive network bridging as business systems have generally been constructed using EtherNet or other general purpose communications networks, whereas specialized networks have been utilized for networked control system components.
The desire to integrate the business and control network structures to interconnect industrial control systems with general purpose systems has led to introduction of industrial EtherNet networks, such as EtherNet/IP networks that have attained some amount of success in allowing direct connection of field devices to an EtherNet network. However, many types of field devices, such as specialized sensors and other low volume devices are not currently offered with industrial EtherNet communications capabilities. Furthermore, the cost for incorporating EtherNet communications functionality is prohibitive for low cost sensors, whereby even if EtherNet/IP compliant devices are available, these are generally more costly than equivalent Fieldbus devices. As a result, constructing a system using exclusively EtherNet/IP devices may be impractical. Thus, while certain EtherNet/IP capable field devices are slowly being introduced, many commercially available Fieldbus compliant devices, such as actuators, motors, valves, etc. remain more cost-effective although not adapted to communicate directly on industrial EtherNet networks. These field devices typically provide communication using device networks including conventional industrial Field bus networks. Currently, such Field bus-ready devices are widely available and are often the most cost effective choice for a variety of control applications. In order to connect such Fieldbus devices to industrial EtherNet networks, therefore, linking devices are needed, such as DeviceNet-to-EtherNet/IP bridges. However, such connections occupy an EtherNet network node and add to system configuration and maintenance complexity. Thus, there remains a need for improved apparatus and methods for cost-effective connection of new and existing control systems to EtherNet and other general purpose networks that allow the use of widely available lower cost Fieldbus adapted devices.